<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>item order</title>
    
    <style>
        .container{
            margin: 0 10px;
            background-color: #ccc;
            display: flex;
            justify-content: space-around;
            height: 40px;
        }
        
        .header-input{
            order: 2;
            width: 80%;
            padding: 5px 10px;
            max-width: 500px;
            border: black solid;
            border-radius: 6px;
        }

        .header-city{
            order: 3;
            width: 10%;
            min-width: 60px;
            align-self: center;
            text-align: center;
        }
        .header-back{
            order: 1;
            width: 10%;
            min-width: 60px;
            align-self: center;
            text-align: center;
        }
        
    </style>

</head>
<body>
    <div class="container">
        <input type="text" class="header-input" placeholder="请输入">
        <div class="header-back">返回</div>
        <div class="header-city">城市</div>
    </div>
</body>
</html>